1. Field of the Invention
The present invention relates to an apparatus for mixing fluids and particularly to a mixer for mixing fluids while permitting the fluids to pass therethrough.
2. Description of the Prior Art
Various types of agitating and mixing devices have been utilized in chemical reactions such as pH adjustment, redox reaction and other reactions. With the recent development of biotechnology, agitation and mixture are becoming more important in the biological field in bacteria cultivation and so on.
One of such devices is a static mixer which is broadly used to mix a liquid with another liquid or a gas. Such a static mixer comprises various types of agitators which are disposed within pipes through which fluids to be mixed pass. These agitators create a turbulence that promotes the mixing. Typically, the agitators are in the form of a cut screw arranged within a pipe.
There has also been proposed such a mixer that includes an agitator disposed within a pipe and connected to a shaft. This shaft oscillates to promote mixing.
One of the agitators often used in such a mixer comprises a spiral-shaped stirring vane which includes a plurality of openings formed therein with one opening in a spiral turn being out of phase relative to another opening in the adjacent spiral turn. It has been found that such an agitator is very effective in stirring and mixing.
It is believed that in such a stirring vane, the fluid flows into each axial spacing or stage between each adjacent spiral turn through both a spiral channel defined by the spiral vane and a passage defined by the opening in the stirring vane and then impinge against each other in that spacing or stage to promote the mixing effect. At the same time, it is also anticipated that since the surface area of the spiral stirring vane is very large, the flow of fluid can be brought more effectively into contact with the surface of the spiral vane to promote the mixing operation by the oscillation of the agitator.
Although the aforementioned mixers can satisfactorily stir and mix fluids, it may be desirable that the agitation is increased depending on the type of fluid to be mixed. If the efficiency of mixture is further increased, the throughput in the mixer may be increased and the size of the entire system may be reduced.